Contents

Prerequisites for Implementing 6PE

The following prerequisites are required to implement 6PE:

•You must be familiar with MPLS and BGP4 configuration and troubleshooting.

•You must be in a user group associated with a task group that includes the proper task IDs for MPLS 6PEcommands. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of Cisco IOS XR System Security Configuration Guide.

Information About 6PE

To configure the 6PE feature, you should understand the following concepts, which are described in the following sections:

Overview of 6PE

Multiple techniques are available to integrate IPv6 services over service provider core backbones:

•Dedicated IPv6 network running over various data link layers

•Dual-stack IPv4-IPv6 backbone

•Leveraging of an existing MPLS backbone

These solutions are deployed on service providers' backbones when the amount of IPv6 traffic and the revenue generated are in line with the necessary investments and the risks agreed to. Conditions are favorable for the introduction of native IPv6 service, from the edge, in a scalable way, without any IPv6 addressing restrictions and without putting a well-controlled IPv4 backbone in jeopardy. Backbone stability is key for service providers that recently stabilized their IPv4 infrastructure.

Service providers running an MPLS/IPv4 infrastructure follow the same trends, as several integration scenarios are possible to offer IPv6 services on an MPLS network. Cisco Systems specially developed Cisco 6PE, or, IPv6 Provider Edge Router over MPLS, to meet all of those requirements.

Inter-AS support for 6PE requires support of Border Gateway Protocol (BGP) to enable the address families and to allocate and distribute the PE and ASBR labels.

Benefits of 6PE

Service providers that currently deploy MPLS will experience the following benefits of Cisco 6PE:

•IPv6 introduction into an existing MPLS service—6PE routers can be added at any time.

•It is possible to switch up to OC-192 speed in the core.

Deploying IPv6 over MPLS Backbones

Backbones enabled by 6PE (IPv6 over MPLS) allow IPv6 domains to communicate with each other over an MPLS IPv4 core network. This implementation requires no backbone infrastructure upgrades and no reconfiguration of core routers, because forwarding is based on labels rather than on the IP header itself. This provides a very cost-effective strategy for IPv6 deployment.

Additionally, the inherent virtual private network (VPN) and traffic engineering (TE) services available within an MPLS environment allow IPv6 networks to be combined into VPNs or extranets over an infrastructure that supports IPv4 VPNs and MPLS-TE.

IPv6 on the Provider Edge and Customer Edge Routers

Service Provider Edge Routers

6PE is particularly applicable to service providers who currently run an MPLS network. One of its advantages is that there is no need to upgrade the hardware, software, or configuration of the core network, and it eliminates the impact on the operations and the revenues generated by the existing IPv4 traffic. MPLS is used by many service providers to deliver services to customers. MPLS as a multiservice infrastructure technology is able to provide layer 3 VPN, QoS, traffic engineering, fast re-routing and integration of ATM and IP switching.

Customer Edge Routers

Using tunnels on the CE routers is the simplest way to deploy IPv6 over MPLS networks. It has no impact on the operation or infrastructure of MPLS and requires no changes to the P routers in the core or to the PE routers. However, tunnel meshing is required as the number of CEs to connect increases, and it is difficult to delegate a global IPv6 prefix for an ISP.

Figure 22 illustrates the network architecture using tunnels on the CE routers.

Figure 22 IPv6 Using Tunnels on the CE Routers

IPv6 Provider Edge Multipath

Internal and external BGP multipath for IPv6 allows the IPv6 router to load balance between several paths (for example, same neighboring autonomous system (AS) or sub-AS, or the same metric) to reach its destination. The 6PE multipath feature uses multiprotocol internal BGP (MP-IBGP) to distribute IPv6 routes over the MPLS IPv4 core network and to attach an MPLS label to each route.

When MP-IBGP multipath is enabled on the 6PE router, all labeled paths are installed in the forwarding table with MPLS information (label stack) when MPLS information is available. This functionality enables 6PE to perform load balancing.

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